KR20210021529A - Plasma source and how it works - Google Patents

Abstract

The plasma source 100 includes an outer surface 10 having an opening 14 for transmitting plasma from the opening. The transfer mechanism is configured to transfer the substrate 11 and the plasma source relative to each other in parallel to the outer surface, the substrate surface being treated parallel to at least a portion of the outer surface defining an opening. The first tile 4-1 and the second tile 4-2 are the first plane of the working electrode 22 together with the adjacent edge 12 bordering the first plasma collection space 6-1. The third tile 4-3 is arranged in the second plane of the working electrode parallel to the first plane so that the third tile overlaps the neighboring edge of the first plane. At least one of the working and counter electrodes includes a local deformation (13, 15) near the neighboring edge to increase plasma delivery to the aperture to compensate for the loss of plasma collection due to the neighboring edge.

Description

Plasma source and how it works

The present invention relates to a plasma source device, in particular a source device of the kind comprising a collection space in communication with an opening, from which the plasma can be transferred to the surface of a substrate to be treated. Such a device is known from WO2015199539. In the device, the first plasma collection space is formed at least partially between the first surface of the counter electrode and the first surface of the working electrode, and the second plasma collection space faces the second surface of the counter electrode and the first surface of the working electrode. It is formed partially between the second side of the working electrode.

Plasma treatment of the surface has many useful applications including the release of the surface, modification of surface energy to improve wettability or adhesion of materials such as paint adhesives and other coatings, cleaning and/or inactivation of bacterial cells on the surface. It is included as a part of large assemblies for surface treatment used in the semiconductor industry, for example chemical vapor deposition, plasma etching, atomic layer deposition and atomic layer etching apparatus. The plasma collection space as disclosed in WO2015199539 is formed between a central flat tile type high voltage electrode encapsulated by a dielectric barrier and disposed at a distance between a pair of grounded outer electrode surfaces. Using an appropriate gas flow from the inlet, the plasma generated in this space can be transferred to an opening that is delivered to the surface of the substrate to be treated. WO2015199539 uses a ceramic dielectric barrier layer on a high voltage electrode to obtain a controlled low current density essential for plasma homogeneity.

Transfer to the substrate can be made effective and uniform by carefully controlling important parameters such as the thickness, composition and roughness of the dielectric layer, the shape of the external electrode, the width of the opening and the angle of plasma transfer. It is important to note that in the reported arrangement, the plasma generated in both spaces contributes to the total flux of plasma delivered from the aperture.

The plasma source disclosed in WO2015199539 was implemented in a surface treatment tool and was used, for example, in a deposition process for an indium (gallium) zinc oxide semiconductor and a low temperature thin film encapsulation layer. Both processes can potentially be applied to, for example, manufacturing OLED displays. WO2008038901 discloses a plasma generator used to treat a substrate by generating plasma under atmospheric pressure and directing the generated plasma out of the plasma generation space to bring the plasma into contact with the surface of the substrate.

An important goal of future generation manufacturing processes is the treatment of increasingly large surfaces, for example 0.5 to 3 meters wide. To this end, some plasma processing tools target plasma sources capable of uniform plasma deposition over the entire width of this surface. Taking into account stringent dimensional tolerances, for example for ceramic elements (thickness, flatness and roughness), e.g. within 10 or 20 micrometers, and a wide temperature range of 20 to 350 °C in which the plasma source should be applied. In consideration, this is a problem since it is difficult to upscale the current plasma source to, for example, 3m width.

In order to facilitate the processing of large substrates by plasma species, an apparatus comprising a plurality of elements arranged in a linear array has been presented (see Fig. 1A). However, when a linear array of elements is used, no plasma is delivered to the area of the substrate passing below the boundary between these individual elements. As disclosed in WO02094455A1, a linear array of multiple rows may consist of each successive row moved to form overlapping processing elements. Or alternatively, as described in US20160289836A1, which discloses an arrangement in which the individual elements of the array can be arranged in an imbricated manner in the direction of a row, i.e. like a shingle on a roof. However, both disclosures fail to some extent for the purpose of providing homogeneity in plasma delivery to the substrate and/or covering a large portion of the substrate in the transport direction due to the residual presence of the region affected by the interface between the individual elements. This is cumbersome because the substrate is sensitive to long-term heating at high temperatures and there are also cost constraints aimed at minimizing the range of the plasma delivery system. Therefore, the orientation of FIGS. 1B-D may provide more uniform transmission, but may be exposed to high temperatures for a long time. As the number of elements increases, problems arise that need to be solved.

In one aspect, the present invention aims to overcome these drawbacks while enabling uniform treatment of large surfaces.

Above all, it is an object to provide a plasma source and/or a surface treatment apparatus for efficient transport and uniform delivery of reactive plasma species having a short lifetime on the surface of a substrate.

A plasma source according to claim 1 is provided.

The plasma source includes an outer surface having at least one opening for transmitting plasma from the opening. A transport mechanism is configured to transport the substrate and the plasma source relative to each other in parallel to the outer surface, the substrate surface being treated parallel to at least a portion of the outer surface defining an opening. The counter electrode comprises at least first and second generally parallel oriented faces extending in a direction away from the substrate, the working electrode comprising multiple planar tiles, the tile being at least by a dielectric layer. At least one partially enclosed film-like conductive layer. At least two plasma collection spaces communicate with at least one opening, the first plasma collection space is formed at least partially between the first surface of the counter electrode and the first surface of the working electrode, and the second plasma collection space is the counter electrode Is formed at least partially between the second side of and the second side of the working electrode. A gas inlet provides gas flow through at least two plasma collection spaces to the opening. The first and second tiles are arranged in the first plane of the working electrode with adjacent edges bordering the first plasma collection space, and the third tile is arranged in a second plane of the working electrode parallel to the first plane. A third tile overlaps the neighboring edge of the first plane. At least one of the working and counter electrode includes a local modification near the neighboring edge to increase plasma delivery to the aperture to compensate for the loss of plasma collection due to the neighboring edge.

In an embodiment, the deformation includes providing a geometrical deformation of the second surface of the counter electrode located side by side next to the neighboring edge of the first plane. Since deformation can improve gas flow, more plasma can be generated on the opposite side of the tile, in locations where plasma generation is disturbed.

In yet another embodiment, the local modification includes providing a geometrical modification to the film-like conductive layer of the tile overlapping the adjacent edge. Specifically, the film-type conductive layer may be partially oriented along the transport direction of the substrate, and the film-type conductive layer is the neighboring edge to enlarge the area of the working electrode in which the plasma can be associated at a position in a straight line with the adjacent edge. And extending in a direction oriented along the transport direction of the substrate away from the edge. By compensating the shape of the working electrode, in particular the bottom surface, the generation of the plasma can be promoted by extension of the conductive layer to compensate for the reduced generation near the adjacent edge. It is noted that the transfer direction of the substrate to the surface treatment apparatus can be reversed in a reciprocating fashion.

Plasma sources are particularly suitable for use in atomic layer deposition (ALD) where the substrate is repeatedly exposed to a series of reactants (at least two) that provide surface-limited layer growth. The plasma source can be used to provide one or more of the continuous reactants and a series of plasma sources can be used. Plasma sources providing highly reactive plasma species make it possible to reduce the space and/or time required for the co-reactants to react with the surface until saturation. This can increase the substrate speed of spatial ALD processing. In other embodiments, plasma sources may be used for other atmospheric plasma surface treatment applications that require chemically reactive plasma species (radical, ionic, electron and vibrationally excited species) to react with the surface. Examples of such applications are cleaning or etching by oxidation (eg using O radicals) or reduction (using H radicals), activation to improve adhesion, and plasma enhanced chemical vapor deposition (PECVD).

_{The gaseous composition is N 2} , O ₂ , H ₂ , H ₂ O, NO, H ₂ O ₂ , NH ₃ , N ₂ O or CO ₂ and mixtures to generate radicals such as N, O, H, OH and NH It may include.

These and other objects and advantageous aspects will become apparent from the description of exemplary embodiments with reference to the following drawings.
1(ad) shows a schematic diagram of a stacked plasma delivery arrangement for producing a uniform deposition on a substrate.
2A-C show side views of a plasma source in one variation.
3A-C show side views of a plasma source in yet another variation.
4 shows another embodiment.

2A shows a cross-sectional view of an exemplary embodiment of a surface treatment apparatus 100 for treating a substrate 11. The substrate 11 may be, for example, a rigid plate such as a semiconductor wafer or part of a flexible foil. In the illustrated embodiment, the surface treatment device has a flat planar outer surface 10 facing the substrate 11, but a curved shape may alternatively be used. In an exemplary embodiment, the distance between the outer surface 10 and the substrate 11 is 0.01 to 0.2 mm or at most 0.5 mm. The openings 14-1 and 14-3 of the outer surface 10 are used to supply atmospheric pressure plasmas 6-1 and 6-3 to the space between the substrate 11 and the outer surface 10. As used herein, the atmosphere means that there is not an effective vacuum between 0.1 and 10 Bar, for example. In the embodiment, the openings 14-1 and 14-3 have a width of 0.1 mm, but this may vary according to design specifications. The openings 14-1 and 14-3, which may also be referred to as nozzles, extend along a line perpendicular to the plane of the drawing. The surface treatment apparatus includes a transfer mechanism for transferring the substrate 11, the first and second counter electrodes 3-1, 3-3 of an electrically conductive material (preferably the same as the substrate when grounded or the substrate is not grounded). At electric potential), comprising an electrically conductive material forming a working electrode 22 oriented in a central position between the two sides (3-1, 3-3) of the counter electrode, and multi-planar tiles (4-1, 4- It includes a dielectric tile (4-1, 4-3) including 3). The tile includes film-like conductive layers 2-1, 2-3 at least partially surrounded by dielectric layers 1-1, 1-3. The plasma collection space is formed between the counter electrodes 3-1 and 3-3 and opposite the tiles 4-1 and 4-3 forming the working electrode 22. The working electrode is located in the center of the opening and extending away from it, and depending on the bottom shape, in the form of a slit, two plasmas in effective communication with the opening 14 or with the respective opening slits 14-1, 14-3 Effectively forming two openings 14-1 and 14-3 of the plasma collection spaces 6-1 and 6-3 extending laterally on the opposite side of the tiles 4-1 and 4-3 having a collection space. can do. The counter electrode may be formed of stainless steel, titanium (preferably), or a conductive ceramic, for example hydrogen doped SiC. Across the plane showing the counter electrodes 3-1 and 3-3, the working electrode 22 extends at least along the length of the opening 14. Further, the surface treatment device may include an electric alternating current or pulsed voltage generator (not shown) connected to the counter electrodes 3-1 and 3-3, and the conductive layers 2-1 and 2-3 are Is part of the working electrode 22 for applying an electric field between the working electrode 22 and on the other hand the counter electrodes 3-1 and 3-3. Alternatively, an electric voltage generator external to the surface treatment device can be used.

The transfer mechanism for the substrate 11 is shown only symbolically. For example, it may include a conveyor belt for transporting the substrate 11 or a table and a motor driving the table, or a roll-to-roll (R2R) mechanism allows the substrate 11 such as foil to be rolled off and rolled over it, respectively. It may be used including the first and second rotating rolls. In another embodiment, the transfer mechanism may include a motor that moves the substrate 11 relative to the assembly of the working electrode 22 and counter electrodes 3-1, 3-3, or vice versa. In another embodiment the electrode may be incorporated into a rotating drum, an opening 14 discharged from the surface of the drum, in which case the conveying mechanism may comprise a motor for directly or indirectly driving the rotation of the drum.

The counter electrodes 3-1 and 3-3 have wedge-shaped portions 9-1 and 9-3, each ending at a pointed edge in the opening 14.

The pointed edges at the bottom of the tiles 4-1 and 4-3 can be supported in part by spacer elements in the opening to ensure adequate spacing of the plasma collection space. This is important for proper generation of (non-filamentary) plasma. For example, wedge-shaped portions 9-1 and 9-3 with flat surfaces are shown, although alternative curved surfaces can be used. For example, first and second wedge-shaped portions 9-1 and 9-3 made of stainless steel can be used. The fact that some have a wedge shape means that their upper and lower surfaces converge towards the pointed edge, that is, their distance decreases. When the upper and lower surfaces run from the edge to a flat plane, they are at an angle to each other, the angle is greater than 0 degrees and less than 90 degrees, preferably between 10 and 60 degrees, more preferably less than 45 degrees, More preferably, it is 30 degrees or less. If a curved upper or lower surface is used, of course there is no fixed angle, but preferably in the orthogonal section line from the edge to the point of the surface at a distance of 3 mm from the sharp edge, the angle in the described range of the flat plane is have.

In an exemplary embodiment, the lower surfaces of the wedge-shaped portions 9-1 and 9-3 lie in a single plane and form the outer surface 10 of the surface treatment device facing the substrate 11.

The working electrode 22 has a surface that is parallel or parallel to some of the surfaces of the wedge shape 9-1 and 9-3 forming the counter electrodes 3-1 and 3-3. The dielectric layers 1-1 and 1-3 cover the surface of the working electrode 22, for example an aluminum oxide dielectric layer may be used. In the embodiment, the working electrode 22 may be realized as a film electrode covered by the dielectric layers 1-1 and 1-3. The dielectric layers 1-1 and 1-3 may be an integral part of the tiles 4-1 and 4-3.

The dielectric barrier discharge plasma collection space is located in the gas volume between the counter electrodes 3-1, 3-3 and the working electrode 22, and the distance between the counter electrode and the dielectric layers 1-1, 1-3 is relatively small. The lower surfaces of the dielectric layers 1-1, 1-3 fit the V-shaped openings, and the upper surfaces of the first and second wedge-shaped portions 9-1, 9-3 of the counter electrode and the dielectric layers 1- It leaves a thin planar plasma collection space for plasma fluid flow in the plasma collection spaces 6-1 and 6-3 between the lower surfaces of 1, 1-3). Preferably, the distance between the upper surfaces of the first and second wedge-shaped portions 9-1, 9-3 and the lower surfaces of the dielectric layers 1-1, 1-3 is limited within this plasma collection space. The dielectric barrier discharge plasma generated in the plasma collection spaces 6-1 and 6-3 is a surface dielectric barrier discharge (SDBD) plasma, and the dielectric layer 1-1, which directly faces the substrate, outside the plasma collection space. 1-3) can be extended to the surface part. If the overall width of the opening 14 is kept small enough, the ionized plasma is not transmitted to the substrate even if the substrate is conductive and at very small distances. In this way, a remote SDBD plasma can be effectively generated at a very close distance from the substrate without using the substrate as an electrode. This is important for applications where high radical flux is required without directly damaging the substrate by plasma. The optimum width of the opening depends on the spatial spacing between the substrate and the dielectric layer 2 of the working electrode 22. For the spacing between the working electrode and the substrate in the range of 0.1-0.3 mm, the possible width of the opening 14 to avoid direct plasma to the substrate is 0.5-2.0 mm, preferably 0.7-1.5 mm.

In operation, an alternating current or pulsed high voltage difference is applied between the counter electrodes 3-1 and 3-3 and the conductive layers 2-1 and 2-3 of the working electrode 22 by a generator (not shown). The counter electrodes 3-1 and 3-3 may be maintained at a constant potential, for example, a ground potential, and a high frequency potential may be applied to the conductive layers 2-1 and 2-3. A gas, which may be a pure gas or a mixture of gases (N ₂ , O ₂ , H ₂ O, H ₂ O ₂ , NO, N ₂ O, H ₂ , NH ₃ , CO _2, etc.), is a gas inlet (5-1, 5-3) and through the planar plasma collection space between the working electrode 22 and the counter electrodes 3-1, 3-3 from the gas inlets 5-1, 5-3 to the opening 14 Flows. The high-frequency electric field in this space due to the voltage difference ionizes the gas while generating plasma. It has been found that nitric oxide (NO) can be used in combination with _{other gases or gases (such as N 2} ), for example to improve the radical density in the plasma collection space. Alternatively or additionally, NO can be added to reduce the gas flow rate required to operate the proposed plasma device.

The ionized gas flows into the opening 14, which forms an atmospheric plasma, i.e., a plasma in the gas of considerable pressure. Atmospheric pressure plasmas tend to turn off rapidly even within periods of high frequency voltages. As a result, the plasma must be restarted periodically for each half cycle of the applied alternating current or pulsed voltage. Plasma may contain free electrons, ions, electrons and oscillatory excited molecules, photons and radicals in addition to neutral molecules. The majority of plasma species are chemically reactive and can be denoted as reactive plasma species (RPS). The properties and concentration of RPS depend on the gas composition and electric plasma conditions. In addition, the rapid recombination process causes a strong change in RPS as a function of space and time. Other examples of RPS are electron or oscillatory excited atoms and molecules. Plasma containing a significant concentration of RPS flows through the opening 14 and from thereto, laterally through the space between the substrate 11 and the outer surface 10 to both sides of the opening 14. Under the opening 14, and to some extent on its side, the RPS interacts with the surface of the substrate 11.

The thickness of the dielectric layers 1-1, 1-3 is chosen to be at least thick enough to avoid discharge through the dielectric layers 1-1, 1-3. There is no fundamental upper limit for the layer thickness, but in order to keep the high frequency voltage required to hold the plasma low, the thickness is preferably below the allowable minimum value. In the exemplary embodiment a thickness in the range of 0.1 to 2 mm, for example 0.15 mm is used. The dielectric barrier can be obtained from an extruded tube, for example a ceramic tube or from a ceramic coated metal tube. The tubular structure provides high intrinsic mechanical strength. The shape may be square, hexagonal, or the like. Two or more surfaces are machined to comply with the mechanical tolerances required for the spacing distance between the working electrode 22 and the counter electrodes 3-1, 3-3. In a practical embodiment, the working electrode is oriented in a central position between the two opposing faces of the counter electrodes 3-1, 3-3 and comprises a multi-planar tile 4, the tile comprising dielectric layers 1-1, 1 And at least one film-like conductive layer (2-1, 2-3) at least partially surrounded by -3). For example, in a Low Temperature Cofired Ceramics process, the tile 4 may be manufactured by layer-by-layer lamination of green ceramic sheets in which a conductive layer is buried and bonded by vias. Instead of sheet-by-sheet manufacturing, slip casting or injection-molded ceramics can be used, where the shape can be molded into the shape before the finalizing step. You can also use 3D printing technology.

A single gas source (not shown) can be used connected to both inlets 5-1 and 5-3. The gas source may comprise a gas mixer having an input connected to the lower source and the lower source for different components of the gas and an output connected to the inlets 5-1 and 5-3.

The gas flow rate (eg, mass or volume per second) from the inlets 5-1 and 5-3 can be selected depending on the desired velocity of the reactive plasma species on the substrate 11. In the example the corresponding mass flow range obtained assuming a velocity of 1000-2000 cubic mm per second, per mm length of opening per inlet, or 1 atmosphere of pressure and a temperature of 25 degrees Celsius is used.

The gas flow velocity through the space between the working electrode 22 and the counter electrodes 3-1 and 3-3 corresponds to the flow velocity divided by the cross-sectional area (thickness times width) of the space. By keeping the cross-sectional area small, a high flow rate is realized. The high flow rate has an advantage that a small loss occurs due to recombination of radicals and ions before reacting in the substrate 11.

2B shows essentially the same cross-sectional view of the plasma source device, but unlike the visible layer 2-3 of the opposing tile 4-3 extending at its cross-sectional position, the edge adjacent to the end of the tile 4-1 Is in a cross-sectional position that does not show the cross-sectional conductive layer. The perspective of Fig. 2C shows a cross-sectional view perpendicular to the plane of the perspective of Figs. 2A and 2B, making this even more clear.

In fact, it can be shown that the tiles 4-1 and 4-2 have adjacent edges 12, and in the cross-sectional view of FIG. 2B only a single electrode 4-3 overlapping the adjacent edges of other tiles is shown. Like the tiles 4-1 and 4-3, the tile 4-2 includes a film-like conductive layer (internal electrode) 2-2 and provides a plasma collection space 6-2 between the tile and the counter electrode. To form.

The cross-sectional view of FIG. 2B shows the near neighboring edge 12 to increase plasma delivery from the counter electrode 3-3 to the opening 6-3 which compensates for the loss of plasma collection due to the neighboring edge 12. Local deformation 13 is shown. In the example, the deformation is provided by geometric deformation of the surface of the counter electrode 3-3 positioned side by side next to the neighboring edge 12. More specifically, the geometric modification includes providing a groove at the location of the second surface to increase gas flow through the second plasma collection space downstream of the groove. The groove functions to increase the flow rate in the plasma collection space opposite the space bordering the adjacent edge. Advantageously, the plasma in the plasma collection space is saturated, thereby increasing the flow, thereby providing a linear increase in the density of chemically reactive plasma species downstream of the plasma collection space. This can be conveniently provided by selecting the channel length of the groove 13 ending at a location away from the opening. Near the opening, preferably, the slit is of a planar shape with a predefined spacing width. On the other side, by increasing the plasma velocity by the groove 13, the plasma delivery in the opening 14 can be made uniform. Although the embodiment shows the groove structure 13 as a local variation, other flow enhancing structures may be designed, such as depressions in the working electrode 22. Preferably, the groove (trench) does not extend to the end of the angular counter electrode 3-3. Reducing the length of a narrow portion of the plasma volume (in the direction of gas flow) is effective enough to increase the mass flow through this volume. The gas flow through the plasma volume downstream of the trench is mainly ^{determined by the coefficient h 3} /L of the narrow section (where h is small) and can therefore be increased by reducing this narrow section.

Providing a plasma collection space 6-3 ending with an opening 14-3 having a uniform and relatively small slit width has the following important advantages.

-The electric field condition applied to this section with increased gas mass flow is the same as the electric field condition applied to two adjacent sections. The homogeneity of the dielectric barrier discharge plasma is highly dependent on the electric field homogeneity and is hardly affected by the locally increased flow.

-The width of the opening 14-3 can be kept smaller than the (minimum) distance between the substrate and the plasma source. In the actual operation of the upscaled system (large substrate widths R2R, S2S), the injector to substrate spacing can vary in the range of 0.1-0.3 mm, thus making the plasma slit spacing h in the plasma collection space 6-3. Enlarging to a larger value is undesirable to prevent gas transfer in the opening 14 in a direction perpendicular to the substrate movement.

An alternative method of obtaining a uniform gas distribution along the length of the slit is to use a porous dielectric material that is permeable to the gas and has a small pore size. The'gap' (h) filled with a porous dielectric in this gas can have a larger width, typically in the range of 0.3-1.0 mm, and pores of a size smaller than this range. The porous layer can be made of a layer on the dielectric barrier which is an integral part of the tiled dielectric barrier element 4 provided, and the dielectric material encapsulating the inner electrodes 2-1, 2-3 is non-porous and has high density and voltage insulation. to be.

Also, on the opposite side of the groove 13 bordering the plasma collection spaces 6-1 and 6-3 near the adjacent edge 12, the working electrode is shown to have a protrusion 15. The protrusion 15 limits the gas flow near the adjacent edge 12 of the tiles 4-1 and 4-2 and balances the overall cross-sectional flow to obtain a flow distribution along the length of the opening. The protrusion is formed, for example, as a single ridge partially connected along the neighboring edge 12, but since it is in the plasma collection space parallel to the neighboring edge, the gas flow in the plasma collection space at a position downstream of the neighboring edge 12 It can be a more complex constriction that reduces the. When in contact with the working electrode 22, the protrusion 15 becomes the length of the plasma gas gap between the counter electrodes 3-1, 3-3 and the dielectric barrier tiles 4-1, 4-3 (0.1 +/- 0.01 mm) high precision and small length can be defined. Closing this ridge prevents non-plasma activating gas flow near the end of the linear dielectric element where no plasma can be generated.

In another aspect of the present invention, Figures 2a-c show external electrically conductive contact regions 7 in which tiles 4-1 and 4-3 are connected to film-like conductive layers 2-1 and 2-3 by via connection. -1, 7-3). The conductive regions 7-1 and 7-3 are formed in electrical conductive contact with the contact regions 7-3 of the tile 4-3, which the tiles 4-1, 4-2, and 4-3 face. One can be integrated into the tile in a way that can be arranged in a stack with the contact area 7-1 of the tile 4-1, so that the film-like conductive layer of the tile can effectively share the same potential. Alternatively, the solid metal strip 8 can be used to connect the contact areas 7-1 and 7-3 and the contact areas 7-2 of the tile 4-2 to effectively share the same potential. Note that the contact area 7-2 of the tile 4-2 is not shown in the cross-sectional view of Figs. 2A-B. As can be seen in Fig. 2c, the tile 2 and each contact area exist in a direction out of the plane of the image of Figs. 2a-b.

3A-C show another example of a local deformation near the neighboring edge of two tiles arranged in a plane to increase plasma delivery to an opening that compensates for the loss of plasma collection due to the neighboring edges. The local modification includes providing an extension of the tile to the film-like conductive layer that overlaps adjacent edges that are partially oriented along the transport direction of the substrate. It is shown in Fig. 3A that extension can be realized by adding conductive layers electrically interconnected, parallel by vias.

3A, parallel planar conductive layers 2-1a and 2-3a having different sizes and positions within the dielectric tiles 4-1 and 4-3 are counter electrodes 3-1 and 3- 3) can be used to control the thickness of the dielectric layer at the bottom of the tile facing the edge-like portions 9-1, 9-3. This is important to obtain a sufficient uniform electric field distribution in the plasma collection spaces 6-1 and 6-3 to uniformly generate plasma. Although two parallel conductive layers of different sizes of each tile are shown in FIG. 3A, a larger number of parallel conductive layers can be used to improve the homogeneity of the electric field applied to the plasma collection space.

Ceramic tiles with inner and outer conductive films can be produced using co-firing techniques in which a stack of printed metal films and ceramic sheets are first assembled and then fired to obtain a monolithic metal-ceramic structure. have. In general the distance between the conductive layers is in the range of 0.1-1.0 mm, preferably 0.2-0.5 mm. The thickness of the printed co-fired layer is preferably in the range of 0.1-0.2 mm. The metal film preferably has a continuous linear edge, but beyond this edge the metal film need not be closed. The patterned metal film can improve the mechanical and voltage insulation properties of the final co-fired structure.

Fig. 3b shows a cross-section similar to the cross-section shown in Fig. 3a but at a different location along the opening 14 near the edge 12 of the dielectric tile 4-1. Due to the absence of conductive layers near the edge of the tiles 4-1 and 4-2, little or no plasma will be generated at this location. The loss of plasma collection is compensated for by adding more conductive layer to the opposing tile 4-3 at the location of the edge.

3A and 3B, the conductive layer 2-1a, 2-3a in each tile 4-1, 4-3 is a contact layer 7 present in the central part of the outer surface of the tile. -1, 7-3). The contact area of the opposite tile is used to form the working electrode 22 by supplying the same high frequency voltage to all conductive layers of the successive dielectric tile.

3C shows different cross sections of the working electrode 22 and counter electrodes 3-1 and 3-3. Different conductive layers positioned parallel inside the dielectric tile have different lengths in the direction of the elongated opening 14. The absence of plasma collection near the edge of the tiles 4-1 and 4-2 is compensated for by the additional conductive layers of the opposite tile 4-3. As visualized in the cross section shown in FIG. 3C, multiple conductive layers of the working electrode 22 can be used to form a triangular-shaped plasma formation region. The length of the plasma formation region in the substrate movement direction gradually increases toward a position parallel to the adjacent edge. Thus, a plurality of film-like conductive layers are provided on the tile and are at least partially surrounded by a dielectric barrier facing the substrate. The film-like layer 2-1a has an edge along the length of the opening 14 to form a pattern of parallel edges crossing the width of the opening. For example, as can be seen in reference numeral 2-1a, the width of the pattern across the opening increases toward a position parallel to the adjacent edge.

In this embodiment, the plasma may be formed not only with the plasma collection spaces 6-1 and 6-3 of FIG. 3A, but also the volume between the substrate and the bottom surfaces of the dielectric tiles 4-1 and 4-3. It can be extended according to the size and position of the parallel conductive film. As a result, a relatively strong electrical interaction between the plasma and the substrate can occur depending on the substrate conductivity and whether the conductive substrate is connected to a fixed potential or is electrically floating.

The assembly of parallel conductive layers improves plasma homogeneity in particular in the direction of the elongated opening 14. By using multiple conductive layers in the dielectric tile, a uniform distribution of plasma-generated reactive radical fluxes towards the moving substrate is obtained.

The plasma generated inside the opening 14 in the bottom surface of the dielectric tiles 4-1 and 4-3 results in a high radical flux, which is dominated primarily by gas diffusion and much less dominated by gas flow. Nevertheless, the use of gas flow through the plasma collection spaces 6-1 and 6-3 towards the substrate 11 is advantageous conditions (electrons, anions, energetics) for uniform plasma extension in the opening 14. Excited molecules).

The plasma formed in the relatively wide opening 14 may be referred to as a'plan-parallel' plasma that is independent of certain types of electrical interactions with a dielectric, grounded conductive, or floating potential conductive substrate.

The radical flux of this planar-parallel plasma to the substrate is primarily diffusion controlled, but the flow transport through the planar-parallel section enlarges the reaction zone to a larger surface area than the opening 14, and counter electrodes 3-1, 3 It extends to the volume between the outer surfaces 10 of -3). The transfer by flow will be caused by the drag flow caused by the relative movement between the outer surface 10 and the substrate 11 of the surface treatment apparatus 100. It is advantageous to further control the flow direction in the volume between the plasma injector and the substrate. Flow direction control is possible by using plasma gas flow rates induced at different pressures through gas inlets 5-1 and 5-3 and plasma collection spaces 6-1 and 6-3. It is advantageous to use the pressure induced gas flow and the substrate movement induced drag flow in the same direction so as not to interfere with each other. When the substrate transfer direction is reversed in a reciprocating manner, it is preferable to change the relative gas flow rate through the gas inlets 5-1 and 5-3 accordingly.

4 shows an alternative embodiment of a surface treatment apparatus 100 in which a plasma source is incorporated in an injector head to provide purge gas and exhaust. This type of injector head is particularly useful for spatial atomic layer deposition or spatial atomic layer etching (spatial ALD/ALE) where thin layers are deposited or etched through a series of gas injectors and through them along the exhaust channels. In spatial ALD, the substrate is a coating precursor gas (e.g., trimethylaluminum (TMA) or trimethylindium (TMI)), _{a purge gas that removes a non-surface reactive precursor gas (N 2} ), a co-reactant (e.g., plasma generation Radical) and finally to non-surface-reactive compounds (eg O ₃ , H ₂ O, H ₂ O ₂ ).

It is important to reduce the size of the injector head in spatial ALD/ALE applications. This is possible by using an injector head as shown in Fig. 4 comprising a plasma source according to the invention. The width of the working electrode 22 is a central electrical contact 7 which can be connected via an electrical connection strip 8 to an external high-frequency voltage generator in a lateral position outside of the plasma treatment zone defined by the length of the opening 14. It is made relatively small with ceramic dielectric tiles 4-1 and 4-3 providing ). The width of the working electrode is generally in the range of 2-4 mm.

Since most types of radicals react very quickly at the surface by gaseous recombination, the useful length of radical exposure along the flat surface of the outer opening 14 and counter electrodes 3-1, 3-3 is up to several mm. to be.

The embodiment of the plasma source and surface treatment apparatus as shown in FIG. 4 is particularly compact and well suited for processing a moving substrate within a short plasma exposure time.

The small lengths of the working electrode 22 and counter electrode 3 provide additional advantages. The reactive plasma can be used as a heat source to improve the reactivity of plasma reactive species. A nearby exhaust channel 16 and purge gas injector 19 allow rapid cooling of the upper surface layer of the substrate after plasma exposure. An additional feature of the surface treatment device and the integrated plasma source allows more effective gas heating by the plasma source. The width 20 of the counter electrode 3 can be made small to limit heat conduction losses from the bottom portion of the plasma source to the injector head. Also insulating material 21, for example ceramic material, can be used to limit heat conduction losses.

It is emphasized that thermally enhanced plasma injectors are not intended for high temperature (thermal plasma). The temperature rise reached by the dielectric barrier discharge plasma source is in the range of 20-100°C. In the end, depending on the gas flow rate and plasma power, determined by the use voltage and frequency supplied by the power generator, the actual value of the temperature rise is 20-50°C. For example, a heated DBD plasma source in operation can be applied to any other temperature sensitive substrate or PET foil at an average foil temperature of 100°C using an injector head to rapidly layer-by-layer annealing the top surface of the substrate at 120-150°C. Can be used to process.

When the term dielectric layer is used, it should be understood that this layer need not have the same thickness everywhere. Although embodiments have been described in which gas from the opening can additionally be used to create a gas bearing between the substrate and the outer surface of the first electrode, it should be understood that such a gas bearing is not always required. If the substrate is a soluble foil, this is very useful, but if a rigid substrate is used (i.e. a substrate that does not deform to such an extent that the distance to the outer surface can vary significantly, for example, 20% or more), contact spacers adjacent to the end of the opening and Another method of maintaining the distance between the same outer surface and the substrate can be used.

This application applies to the terms'a' through'o' listed below. It will be understood that aspects of these provisions may be combined with other aspects of the invention, for example as described in the claims. For example, clause'a' in which the tile includes an external electrically conductive contact area connected to a film-like conductive layer, and the tiles are arranged in a stack so that the contact area of the first tile is in electrical conductive contact with the contact area of the opposite tile. The plasma source, as described in', includes a local deformation in the vicinity of the neighboring edge with at least one of the working and counter electrodes to increase plasma delivery to the aperture to compensate for the loss of plasma collection due to the neighboring edge. It can be combined with aspects of various embodiments of a plasma source.

By providing a tile to a plasma source having an external electrically conductive contact area connected to the film-like conductive layer tile in a stack, the film-like conductive layer of the tile can effectively contact to share the same potential. In addition, providing an external electrically conductive contact area is a central electrical contact which can be connected to an external high frequency voltage generator via a connecting strip 8 at a lateral position outside the plasma treatment area defined by the length of the electrical opening 14. With the ceramic dielectric tiles 4-1 and 4-3 providing 7), the width of the working electrode 22 can be relatively reduced.

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a. Plasma source,

-An outer surface comprising at least one opening for transmitting plasma from the opening;

-A transfer mechanism configured to transfer the substrate and the plasma source relative to each other in parallel with the outer surface, the substrate surface being treated parallel to at least a portion of the outer surface defining an opening;

-A counter electrode comprising at least first and second generally parallel oriented surfaces extending in a direction away from the substrate;

-A working electrode comprising at least two at least partially overlapping planar tiles-the tile comprising a film-like conductive layer at least partially surrounded by a dielectric layer;

-At least two plasma collection spaces communicating with at least one opening-The first plasma collection space is formed at least partially between the first surface of the counter electrode and the first surface of the working electrode, and the second plasma collection space is the counter electrode Formed at least partially between the second side of the working electrode and the second side of the working electrode;

-A gas inlet for providing gas flow through at least two plasma collection spaces to the opening;

Including,

-The tile comprises an external electrically conductive contact area connected to the film-like conductive layer,

-The tiles are arranged in a stack so that the contact area of the first tile is in electrical conductive contact with the contact area of the opposite tile.

b. In the plasma source according to clause a, the electrically conductive connection is provided by an electrically conductive via.

c. In the plasma source according to clause a, the electrically conductive connection is provided by a strip of film-like conductive layer running along the outer surface of the tile to the outer electrically conductive contact area.

d. The plasma source according to clause a, wherein the stack further comprises a conductive plate element provided between the outer electrically conductive contact areas of the opposing tiles.

e. In the plasma source according to clause a, the width of the surface of the counter electrode, which is the closest surface of the substrate to be processed along the moving direction of the substrate with respect to the counter electrode, is 1 in order to reduce heat transfer from the electrode to the substrate to be processed. Available in -4 mm range.

f. In the plasma source according to any one of clauses a-e,

-In the stack, the first (4-1) and second tiles (4-2) are arranged in the first plane of the working electrode together with the adjacent edge bordering the first plasma collection space, and the third tile (4) -3) is arranged on the second plane of the working electrode parallel to the first plane so that the third tile overlaps the neighboring edge of the first plane,

-At least one of the working electrode 22 and the counter electrode 3-1, 3-3 is localized near the neighboring edge to increase plasma delivery to the opening to compensate for the loss of plasma collection due to the neighboring edge. Includes transformation.

g. In the plasma source according to clause f, the local deformation comprises a geometric deformation provided on the second side of the counter electrode positioned next to the neighboring edge of the first plane.

h. In the plasma source according to clause g, the geometrical modification comprises a groove 13 provided in the position on the second side to increase the gas flow rate through the second plasma collection space downstream of the groove.

i. The plasma source according to clause h is provided in the first plasma collection space parallel to the neighboring edge, and thus further comprises a partial constriction 150 to reduce the gas flow of the first plasma collection space at a position downstream of the neighboring edge. .

j. In the plasma source according to clause i, the partial contraction damages the ridge 15 provided on the first side of the counter electrode in a position parallel to the neighboring edge.

k. In the plasma source according to clause f, the local modification comprises a plurality of film-like conductive layers (2-1a, 2-3a) provided on the tile, at least partially surrounded by a dielectric barrier facing the substrate, The film-like layer has an edge along the length of the opening to form a pattern of parallel edges across the width of the opening.

l. In the plasma source according to clause k, the pattern has a width across an opening that gradually increases toward a position parallel to an adjacent edge.

m. In the plasma source according to clause f, the local modification comprises an extension provided in the film-like conductive layer of the tile overlapping an adjacent edge, oriented partially across the width of the opening.

n. In the plasma source according to clause m, the length of the extension gradually increases toward a position parallel to the adjacent edge.

o. For the plasma source according to clause f, the geometric modification comprises a reduced thickness of the dielectric barrier for the tile in the second plane at a location parallel to the neighboring edge to locally increase the electric field strength.

Claims (16)

In the plasma source 100,
-An outer surface 10 comprising at least one opening 14 for transmitting plasma from the opening;
-A transfer mechanism configured to transfer the substrate 11 and the plasma source relative to each other along the outer surface;
-A counter electrode including at least a first surface (3-1) and a second surface (3-3) extending in a direction away from the substrate;
-Working electrode comprising multiple planar tiles (4-1, 4-2, 4-3)-The tile is at least one film surrounded at least partially by dielectric layers (1-1, 1-2, 1-3) -Including type conductive layers 2-1, 2-2 2-3;
-At least two plasma collection spaces in communication with at least one opening- The first plasma collection space (6-1) is formed at least partially between the first surface of the counter electrode and the first surface of the working electrode, 2 The plasma collection space (6-3) is formed at least partially between the second surface of the counter electrode and the second surface of the working electrode;
-A gas inlet (5) for providing gas flow to the opening through the at least two plasma collection spaces;
Including,
-The first tile 4-1 and the second tile 4-2 are arranged in the first plane of the working electrode together with the adjacent edge 12 bordering the first plasma collection space, and the third tile (4-3) is arranged on a second plane of the working electrode parallel to the first plane so that the third tile overlaps the adjacent edge of the first plane,
-At least one of the working electrode 22 and the counter electrode comprises a local deformation near the neighboring edge to increase plasma delivery to the opening compensating for loss of plasma collection due to the neighboring edge. sauce.
The method of claim 1,
The local deformation includes a geometric deformation provided to the second surface of the counter electrode at a position parallel to the adjacent edge of the first plane.
The method of claim 2,
Wherein the geometrical deformation includes a groove (13) provided at the position of the second surface to increase the gas flow rate through the second plasma collection space downstream of the groove.
The method of claim 3,
The plasma source further comprising a partial contraction 150 provided in the first plasma collection space parallel to the neighboring edge to reduce the gas flow of the first plasma collection space at a position downstream of the neighboring edge .
The method of claim 4,
The partial contraction damages a ridge (15) provided on the first side of the counter electrode in a position parallel to the adjacent edge.
The method of claim 1,
The local modification includes a plurality of film-like conductive layers (2-1a, 2-3a) provided on the tile, at least partially surrounded by a dielectric barrier facing the substrate, wherein the film-like layer comprises the opening And having an edge along the length of the opening to form a pattern of parallel edges across the width of the plasma source.
The method of claim 6,
Wherein the pattern has a width across the opening that gradually increases toward a position parallel to an adjacent edge.
The method of claim 1,
The local modification comprises an extension provided to the film-like conductive layer of a tile overlapping an adjacent edge, oriented partially across the width of the opening.
The method of claim 8,
The plasma source, wherein the length of the extension gradually increases toward a position parallel to an adjacent edge.
The method of claim 1,
Wherein the geometrical modification comprises a reduced thickness of the dielectric barrier for the second planar tile at a location parallel to the neighboring edge to locally increase the electric field strength.
The method according to any one of claims 1 to 10,
The tile further includes external electrically conductive contact areas 7-1 and 7-3 electrically connected to the film-type conductive layer, and the tiles are arranged in a stack so that the contact area of the first pile is of the opposite tile. In the state of electrically conductive contact with the contact region, the film-like conductive layer of the tile effectively shares the same potential.
In the device according to claim 11,
Wherein the electrically conductive connection is provided by an electrically conductive via.
In the device according to claim 11,
Wherein the electrically conductive connection is provided by a strip of film-like conductive layer running along the outer surface of the tile to the outer electrically conductive contact area.
In the device according to claim 11,
The device, wherein the stack further comprises a conductive plate element (8) provided between the outer electrically conductive contact areas of opposing tiles.
In the device according to claim 11,
In the case of the counter electrode, the width of the surface of the counter electrode, which is the closest surface of the substrate to be processed along the moving direction of the substrate, is provided in the range of 1-4 mm to reduce heat transfer from the electrode to the substrate to be processed. , Device.
A method of operating the device according to claim 1 at an operating temperature exceeding the maximum service temperature of the substrate to be processed, comprising:
The method, wherein the operating temperature is in a range of 20-100°C above the service temperature.

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